The bosses haven’t yet introduced facial recognition technology at the Royal Hawaiian Hotel. But from her perch behind the front desk at the pink neo-Moorish palace overlooking Waikiki Beach, Jean Te’o-Gibney can see it coming.

“Marriott just rolled it out in China,” enabling guests to check into their rooms without bothering with front-desk formalities, said Ms. Te’o-Gibney, a 53-year-old grandmother of seven. “It seems they know they will be eliminating our jobs.”

Similar fears simmer throughout Marriott’s vast network of hotels, the largest in the United States. Over the last two weeks, Ms. Te’o-Gibney and thousands of other Marriott workers — cooks and cashiers, bellhops and housekeepers — have voted to authorize their union, Unite Here, to strike at dozens of locations from Waikiki to Boston and San Diego to Detroit.

Alongside the usual demands for higher wages and better workplace safety, the union is bringing another issue to the table, asking for procedures to protect workers affected by new technologies and the innovations they spur.

“You are not going to stop technology,” said Unite Here’s president, D. Taylor. “The question is whether workers will be partners in its deployment or bystanders that get run over by it.”

Unlike manufacturing workers, whose jobs have been lost to automation since as far back as the 1950s, workers in the low-wage portion of the service sector had remained until now largely shielded from job-killing technologies.

Many earned too little to justify large capital costs to replace them. A typical hotel or motel desk clerk earns just over $12 an hour, according to government data; a concierge just over $13.50. And many of the tasks they perform seemed too challenging to automate. Technology is changing this calculus.

There is no equivalent measure on the penetration of software systems like Alexa or touch screens in the workplace. But in 2014, automakers in the United States had 117 robots for every 1,000 workers, according to research by the economists Daron Acemoglu of the Massachusetts Institute of Technology and Pascual Restrepo of Boston University. In service businesses, there were virtually none.

But with advances in machine learning and other innovations in information technology, many service jobs are now potentially in jeopardy. Compared with manufacturing, the investment needed to automate some tasks in the hotel sector — like front desk or concierge services — is likely to be relatively low.

Maria Mendiola, a concierge at the San Jose Marriott, frets that Amazon’s agreement to deploy its Echo device in hotel rooms across Marriott’s properties will eventually make her position pointless. “Alexa might do my job in the future,” she said.

At the Sheraton Waikiki, next to the Royal Hawaiian, cashiers at the beachside lounge worry about a newly deployed computer system that will allow servers to close out their own checks — making cashiers redundant.

New technologies are reconfiguring the workplace in other ways. Doormen are losing tips as guests turn to Uber and Lyft instead of regular taxis. So are bellhops when guests use Seamless, a food-delivery app, instead of room service.

How many jobs will technology take out? Hoteliers have yet to figure out how guests will react to a more tech-heavy experience. A Marriott spokeswoman said in a statement that the chain was not deploying technology to eliminate jobs but was “personalizing the guest experience and enhancing the stay.”

Cliff Atkinson, senior vice president for hospitality at MGM Resorts, said new technologies had changed job descriptions at properties across his chain but had not eliminated jobs. Front-desk clerks displaced by automated check-in kiosks are deployed as “lobby ambassadors” or concierges.

Still, history suggests that the most powerful motivation to deploy new technologies has been the opportunity to reduce labor costs. From 1993 to 2007, Professors Acemoglu and Restrepo estimated, each new robot cut 5.6 jobs and reduced wages by 0.5 percent.

Image

Cashiers at beachside lounges worry that new technology will allow servers to close their own checks, and a future in which every guestroom has an Echo device troubles concierges.CreditMichelle Mishina-Kunz for The New York Times

As technology gets better and cheaper, there are lots of new tasks it could take over. “It is a new, uncharted area for our company and our industry as a whole,” Mr. Atkinson said. “We have talked about one or two brands being fully automated and self-service for the guest.”

David Autor, an economist at M.I.T., says it is plausible to foresee a future in which — as airlines have done — hotels deploy humans to tend to elite guests and automated systems for everybody else. Workers generate costs well beyond their hourly wage, Professor Autor argued. They get sick and take vacations and require managers. “People are messy,” he noted. “Machines are straightforward.”

Last year, the McKinsey Global Institute issued a report projecting that technology would drive a 30 percent decline in jobs in food service and lodging from 2016 to 2030. That’s almost on a par with the 38 percent decline in manufacturing jobs from 1960 to 2012.

Unions would rather not have manufacturing’s story repeat itself in the service sector. “We are trying to get ahead of that,” said Anand Singh, president of Unite Here’s local in San Francisco. “We are not Luddites, but we are seeking a real voice at table.”

The International Brotherhood of Teamsters is also worried about technologies hurtling into the present. As it squared off for contract negotiations with United Parcel Service this year, the union put a bold proposition on the table: to prohibit using drones or autonomous vehicles to deliver packages. But in September, when the union sent the agreement to members for a ratification vote, there was no such provision.

Edward Wytkind, who until this year headed the Transportation Trades Department of the A.F.L.-C.I.O., said unions could not stop technology if they tried. “Maybe you can stop it through one round of bargaining or slow it down,” he said. “But innovation has been going on for 100 years and has never stopped.”

And he noted what might be the cost of success: “Are we winning a future for workers? Not if the company goes out of business.”

A better strategy might be to demand a say in how technology is deployed.

The Teamsters’ tentative deal with U.P.S., for instance, calls for six months of advance warning to the union of technological deployments and for the creation of a committee with union and company representatives that would negotiate “regarding the effects of the proposed technological changes.”

Image

Members of the Unite Here union have voted to authorize a strike at the Royal Hawaiian and dozens of other Marriott locations over issues that include procedures to protect workers affected by new technologies.CreditMichelle Mishina-Kunz for The New York Times

Unite Here is following a similar path. Mr. Singh listed the union’s goals for Marriott contracts: “We want to talk about how technology can assist the work we perform and ease the rigors of our work, how our members are trained, what happens to workers who would otherwise be tagged as redundant, how our members are repositioned to succeed or hired into other workplaces.”

In June, the union managed for the first time to include protections from technological change in its contracts covering workers at the Las Vegas properties of MGM Resorts and Caesars Entertainment. Workers will be trained to do jobs created or modified by new technology, allowing them to share in the productivity gains. The contracts also provide for the company to try to find jobs for displaced workers. But the union’s key achievement was to get 180 days’ warning of technological deployments.

“They have to let us know and show us the prototypes and must negotiate with us,” Mr. Taylor said. “At the end of the day, they can move forward, but this gives us time to understand the effects.”

If they could choose a precedent from American labor history, today’s union leaders might follow the path of the International Longshore and Warehouse Union.

In the 1960s and ’70s, dockworkers were walloped by one of the most revolutionary technical innovations of the 20th century: containers. At a stroke, containers slashed both the time and number of workers needed to load a ship, saving vast amounts of money.

Instead of trying to stop the big boxes, the union covering the longshoremen on the West Coast demanded a share of the spoils: rich retirement packages for workers who were let go, and hefty remuneration for those who stayed. As a result, longshoremen working full time, year round, now make $168,000 to $186,000 a year on average.

But you need a lot of power to get a deal like that. The longshore union could shut down ports at will, imposing huge costs on shippers. For workers lacking that kind of clout, the gains achieved by the longshoremen seem out of reach.

Unite Here is not powerless. Nationwide, only 7.6 percent of workers in the accommodation industry are unionized, according to government statistics. But in San Francisco, for instance, Unite Here represents 89 percent of workers at Class A hotels. That’s partly why housekeepers in San Francisco make $22.64 an hour, the union notes, more than double the national median of $10.09.

Unite Here’s victories so far have been hard won. “It was not an easy ask,” Mr. Taylor said of the language on technology in the Las Vegas deals. “It does infringe on hotels’ right to do what they want.”

The outcome might or might not deliver a greater share of the gains from technology to workers. But front-desk clerks and concierges will have better options than severance when Alexa or computer software takes over some of their tasks. “It was a good resolution,” Mr. Taylor said. “Time will tell if it is good enough.”

A version of this article appears in print on , on Page A1 of the New York edition with the headline: Hotel Workers Fear the Robot at the Front Desk. Order Reprints | Today’s Paper | Subscribe